Some self-propelled utility vehicles have a drive system in which a trunnion bearing assembly is provided. A conventional trunnion bearing assembly is shown in FIG. 14. Here, the assembly has a bearing encapsulated in a stamped trunnion housing TH and mounted to an inner shaft IS. The trunnion housing is mounted at one end region of the inner shaft and a stamped plate SP is secured (staked) to an opposite end of the shaft. A rubber wheel (not shown) is attached to the stamped plate SP. A hex axle (not shown) is mounted in a hex-shaped internal opening IO of the shaft IS. A shift linkage (not shown) is attached to the trunnion housing TH by virtue of two pins or the like received respectively in two openings OP defined by two trunnions TR of the housing. When the shift linkage is moved to a drive position, the rubber wheel moves into driven engagement with a motor flywheel (not shown), thereby causing conjoint rotation of the rubber wheel, the stamped plate SP, the inner shaft IS, and the axle. In response to this rotation of the axle, at least one driven wheel (not shown) of the vehicle rotates so as to propel the vehicle.
The conventional trunnion bearing assembly of FIG. 14 has drawbacks. They stem from having the inner shaft IS itself define the inner race of the bearing. There is, for example, significant waste (in terms of scrap material) in the machining required to give the exterior of the shaft the contour that defines the inner race. This machining also consumes a considerable amount of tooling. Further, if this machining is not done accurately, then the bearing may not function properly. Moreover, it would be desirable to avoid the secondary operation of having to go back and broach the hex-shaped internal opening IO of the shaft IS. Still further, because the stamped plate SP is staked to one end of the shaft IS, the shaft cannot be hardened sufficiently without great expense. As a result, the inner race wears faster than other bearing components. This shortens the life of the bearing.
It would be desirable to provide a bearing assembly that eliminates the problems associated with conventional trunnion bearing assemblies of the nature described.